Neodymium

Neodymium tarnishes slowly in air, and burns readily, forming neodymium(III) oxide, Nd₂O₃.

4 Nd(s) + 3 O₂(g) 2 Nd₂O₃(s)

Neodymium dissolves readily in dilute sulphuric acid, forming lilac Lu(III) ions and hydrogen gas, H₂.

2 Nd(s) + 3 H₂SO₄(aq) 2 Nd³⁺(aq) + 3 SO₄²⁻(aq) + 3 H₂(g)

Neodymium reacts with all the halogens, forming the corresponding neodymium(III) halides.

2 Nd(s) + 3 F₂(g) 2 NdF₃(s) [violet]
2 Nd(s) + 3 Cl₂(g) 2 NdCl₃(s) [mauve]
2 Nd(s) + 3 Br₂(g) 2 NdBr₃(s) [violet]
2 Nd(s) + 3 I₂(g) 2 NdI₃(s) [green]

Neodymium reacts slowly with cold water, and quickly with hot water, forming neodymium(III) hydroxide, Nd(OH)₃, and hydrogen gas (H₂).

2 Nd(s) + 6 H₂O(l) 2 Nd(OH)₃(aq) + 3 H₂(g)